E01: Triangular Cantilever Plate Eigenvalues
- Gokhan Alkan (Unlicensed)
- Halil Yasavul (Unlicensed)
A triangular cantilever plate is subjected to its own weight. Compute the lowest three natural frequencies of the plate.
The plate is 6.0 inches by 6.0 inches and the thickness is 0.034 inches. The weight density is 0.06414 lb/in3. The elastic modulus of the material is 6,500,000 lb/in2 and Poisson's ratio is 0.3541.
The model used has 66 joints and 55 plate elements. The joints 1 to 11 are fixed in all six (6) degrees of freedom. Since the plate elements do not have any stiffness about the axis perpendicular to the plane of the plate, the rotation about the global Z-axis for joints 12 to 66 are eliminated.
The joint masses are automatically computed by LARSA. The material and sectional property data of the plate structure are given as:
Tested Features
Reference
- "ASME Pressure Vessel and Piping 1972 Computer Programs Verification.", I.S. Tuba and W.B. Wright, ASME publication, I-24, Problem 2.
Sources
- LARSA 4D
- COSMOS7
- NASTRAN
Library Link:
| Model | Output Parameter | OpenBrIM | LARSA | COSMOS7 | NASTRAN | OpenBrIM vs LARSA |
|---|---|---|---|---|---|---|
Triangular cantilever plate | f1(hz) | 55.42 | 55.5 | 55.6 | 55.6 | 0.81% |
| f2(hz) | 203.98 | 204.23 | 206.5 | 206.5 | 0.17% | |
| f3(hz) | 279.08 | 281.33 | 283.1 | 283.2 | 0.13% |